Delineation of simple microecosystems associated with the quartz stone habitat in the Vestfold Hills

Entry ID:
ASAC_992

Summary

Abstract:
Quartz stone sublithic microbial communities and underlying soil, retrieved from the Vestfold Hills were investigated using a variety of traditional and molecular methods. Although direct epifluorescent counts of the sublithic biota averaged 1.1 x 109 cells g-1 dry weight and underlying soil, 0.5 x 109 cells g-1 dry weight, viable counts were on average 3-orders of magnitude higher in sublithic ... samples cf. underlying soil. Enrichment and molecular analyses revealed the predominant cyanobacteria were non-halophilic, able to grow optimally at 15-20 degrees C, and were related to the Phormidium subgroup with several distinct morphotypess and phylotypes present. Sublithic heterotrophic bacterial populations and those of underlying soils included mostly psychrotolerant taxa typical of Antarctic soil. However, psychrophilic and halophilic bacteria, mostly members of the alpha subdivision of the Proteobacteria and the order Cytophagales, were abundant in the sublithic growth (20-40% of the viable count and about 50% of isolated individual taxa) but absent from underlying soils. It is suggested that quartz stone subliths might constitute a 'refuge' for psychrophilic bacteria.